Why are there typically 5 lug-nuts on a mid-sized wheel?

Odd numbers balance better if something goes wrong.

Suppose you put four equal weights/loads/fasteners at 90 separation on an axis, each carries 25% of the load. One breaks off; a vibrational load is introduced. Two of the fasteners contribute nothing to restraining vibration around the axis between them. The third fastener is subject to vibrational forces inversely proportional to its distance from the axis of rotation; the wheel is vibrating around an axis where only one lug nut provides restraint.

If there are five fasteners, and four remain intact, the vibrational forces around the axis of maximal assymetry are distributed among four fasteners, each bearing load inversely proportional to its distance from the axis of maximal assymetry. Forces are proportional to the (absolute value of the) cosine of the angular displacement from the failed fastener, and those farthest from the failed fastener bear the greatest stress. This works out to about 15% (each) of what the lug nut on a 4-lug system would bear. Not a bad improvement for adding ONE lug.

On a three-lug wheel, the vibrational forces (on the two remaining lugs) are nominally 25% less than the forces on the single opposite lug of a four-lug system, but the real vibrational force might rapidly become immensely greater as one or both remaining lug nuts loosen even slightly. Total shear capacity under torque would be also be reduced.

The cts v always had 6 bolt due to v8 motor and bigger brakes and higher speeds? But v8 Camaro had 5 bolt.

Could it be as simple as “Cadillac is supposed to be 1 better than other GM products, and therefore it gets 6 lugs?”

Wouldn’t be the first time Caddy spent money on ostentatious unnecessaries:

The next generation supercharged CTS-V went back to 5 bolt wheels, much to the delight of owners wishing new custom wheels.

You cannot make generalizations even within a single manufacturer.

Maybe it’s got something to do with payload or tow ratings. Camaro is powerful if optioned right, but not intended to tow anything or haul much in the trunk. Unless you’re a super redneck.

Ok, certainly not a Camaro in the pic. That was me in a period when I was without a truck for a while. I took the pic and sent it to my wife who gave me the eyeroll emoji in response. You’ve got to be able to poke fun at yourself!

1 Like

In this area of CA that’s right about the fireplaces, no new wood-burning fireplaces allowed. Haven’t heard about banning gas stations. There’s plenty of gas stations already, not much need for new ones. Rain barrels are allowed, even encouraged. I doubt smudge pots are allowed these days.

I remember driving through northern CA a number of years ago, in the country, fair number of cabins. There were layers of smoke hanging in the air from fireplaces, those things do put out a lot of nasty stuff.

Very true. I wouldn’t object myself if all wood-burning in fireplaces was banned, existing or new. In addition to the air pollution, their banning in new construction can create jealously among owners of new homes. New home owners – despite paying considerably higher property taxes and house payments – wonder why their neighbors owning older houses are allowed to burn wood, while they can’t. Creates neighborhood drama. I think the politicians’ approach to this is to prohibit wood burning on certain days, called “spare the air days”, and to gradually increase the number of those days until there are virtually no days allowed for wood burning.

I hope you’re being sarcastic. I wouldn’t have any idea which of my neighbors have wood burning fireplaces because I just don’t care enough to inspect everyone’s roof hardware.

I wouldn’t mind a ban on wood burning fireplaces for another reason. In my former career I covered way too many house fires started by wood fireplace chimneys. People don’t get their chimneys swept often enough, and think that chimney-sweeping-log thing is good enough. And then their house burns down.


We have no choice but wood heat when the power is out. The fireplace is not optional.

It gets swept every 2-3 ricks and has a spark grate twice as tight as what the county requires. Do you like to see sparks come out the chimney and land on your roof? I do not.

Not being sarcastic at all. Some folks in Calif who own new homes do indeed seem to be bothered by this. Most of course have too many other things on their plates to worry about their neighbor’s fireplaces; but I guess there’s always somebody in any neighborhood who wakes up a little cranky and looking for something to complain about. I had a neighbor years ago who complained that the neighborhood birds were landing in my tree … lol …

Wow. It just wouldn’t occur to me to get jealous over a fireplace. Now, the guy down the street with the 4 post lift? Oh yeah. I’m jealous as hell of him. The jerk. :wink:


Another time a neighbor of mine complained that the work crew repairing my roof that morning had started at 7:45 am, 15 minutes before construction work is allowed. They weren’t pounding nails or doing anything loud, just on top of the roof talking to each other, planning their work plan for the morning.